Heat-exchange apparatus



H. JUNKERS HEAT EXCHANGE APPARATUS Filed June '7 Patented. J an. 27, 1925.

UNITED STATES HUGO JUNKERS, 0F DESSAU, GERMANY.

HEAT-EXCHANGE APPARATUS.

Application filed June 7,

To all whom it may concern:

Be it known that I, Hoe-0 JUNKERS, a citizen of Germany, residing at Dessau, Anhalt, Germany, Cothenerstrasse 27, have invented certain new and useful Improvements in Heat-Exchange Apparatus (for which I have made an application in Germany, August 5th, 1922), and of which the following 1s a specification.

In heat exchange apparatus formed as bodies with the ribs or gills it is known to distribute the entire rib surface over separate groups of ribs, which follow upon each other in the direction of the medium streaming between the ribs.

The invention has for its purpose to improve the economy of such heat exchange apparatus, especially in the use for heating liquids, by setting in such a relation the heat transmission coeflicient and the temperature difference between the heat exchange fluids or gasses in every group, that the said coeflicient is augmented from one group to the next in proportion to the diminishing temperature difference.

This is accomplished by arranging several groups of ribs in the direction of flow of the hot gases and giving to every group a greater rib surface per unit of the current path than in the preceding group, in proportion to the decreasing temperature difference between the heat exchanging media. lVith particular advantage, in addition to the said increase of the rib surface, the groups following upon each other in the direction of the current streaming between them have decreasing thicknesses of the rib walls, and the distance between the ribs decreases from every group to the subsequent. The said decrease of the rib distance produces directly an augmentation of the heat transmission coefficient, and simultaneously the medium streamin between the ribs is forced to adopt a higher velocity, which again augments the heat transmitting coefiicient.

The invention is illustrated in the accompanying drawing, in which Figs. 1 and 2 show w he t e change apparatuses, in

enlarged in order to which is exposed to the hottest 1924. Serial No. 718,582.

section, constructed in accordance with my invention.

According to Fig. 1 a tube 1, through which the water to be heated streams in any desired direction, is bent to such a form that it crosses with several branches a flue leading the heating gases in the direction shown by the arrows a. Each branch is provided wlth ribs 2 in such manner, that the lowest group contains a small number of ribs, the next group a somewhat greater number and so on, The flue is upwardly overcome the restriction to the flow of heated gases caused by the upwardly increasing numbers of ribs.

According to Fig. 2 the heater is of the same general arrangement as in Fig. 1, but in each group the ribs are thinner and arranged at less distances apart than in the preceding group.

This latter form of construction has the following special advantages. The great distances between the ribs in the first group, gases, avoid the deposition of gas residua, and the great thickness of the ribs in this group prevents melting of the metallic coating of the ribs and other destructions by heat, which otherwise might occur. The heating gases entering with the highest tem erature are caused by the small rib sur ace and the small heat transmission coeificient in the first group, to deliver to-these ribs only that amount of heat, which serves for the desired distribution of temperatures, then the said gases are caught in the'second group by an enlarged heat transmission surface, which corresponds to their diminished tem perature, thus givin substantially the same' heat exchan e for the second group as for the first. This is also true for each successive group.

I claim:

A heat exchange apparatus comprising a duct for the passage of a heating medium such as heated gases; a second duct for the passage of a fluid to be heated consisting of a pipe passing transversely through the first named duct at various points between the inlet and outlet thereof, each pipe section through said first named duct being area for each pipe section, and at the same time decrease in thickness and in their distance apart for each pipe section, in the direction of the flow of the heating medium through the first named duct.

In witness whereof I aflix my signature.

HUGO J UNKERS. 

